Projectiles to be launched by means of a firearm and including an auxiliary propulsion motor



Jan. 1,- 1963 R. AMMANN 3,0 1,073

PRQJECTILES TO BE LAUNCHED BY MEANS OF A FIREARM AND INCLUDING AN AUXILIARY PROPULSION MOTOR Filed May 9, 1960 INVEZ 0R United States Patent Ofifice 3,071 ,073 ?atented Jan. 1, 1963 PRUJECTKLES TO BE LAUNtIHED BY MEANS (BE A FIREARM AND INCLUDING AN AUXHLIARY PROPULSIGN MUTOi-l Rudolf Ammann, Geneva, Switzerland, assignor to Brevets Aero-Mccaniques S.A., Geneva, Switzerland, a society of Switzerland Filed May 9, 19%, Ser. No. 27,631 Claims priority, application Luxembourg May 21, 1959 6 Claims. (Cl. 102-49) The present invention relates to projectiles intended to be slidably fitted on the end of a firearm barrel so as to be launched in the manner known for rifle grenades, said projectile being further provided with an auxiliary propulsion motor, advantageously of the rocket type.

In such projectiles, as known up to this time, the firearm imparted an initial acceleration to the whole of the projectile proper and the auxiliary propulsion motor fixed thereto, this auxiliary motor beginning to supply a propulsion thrust only after launching, so that the recoil of the firearm was determined by the total weight of the projectile and its auxiliary propulsion motor. Therefore, other things being equal, recoil was greater than if the projectile had not been provided with an auxiliary propulsion motor.

The object of the present invention is to provide a projectile of this kind which is better adapted to meet the requirements of practice than those used up to now and in particular which is such that the recoil resulting from launching is reduced.

The chief feature of the present invention consists in making the auxiliary propulsion motor slidable axially with respect to the projectile proper between a front abutment and a rear abutment both carried by said projectile, and this in such manner that when the firearm is fired only the projectile is initially accelerated when the firearm is fired and thus is the only part to give rise to a recoil, means being provided to ignite said auxiliary propulsion motor in response to the launching of the projectile so that said auxiliary motor quickly comes to bear against the front abutment of the projectile and then transmits its thrust thereto.

Preferably, said motor is such, and ignited in such manner, that, upon launching, it is accelerated sufiiciently quickly not to be contacted by the rear abutment of the projectile.

A preferred embodiment of the present invention will be hereinafter described with reference to the accompanying drawings, given merely by Way of example and in which:

FIG. 1 is a diagrammatic axial sectional view of a projectile made according to the present invention, fitted on the muzzle end of a rifle barrel.

FIG. 2 is an enlarged view of a portion of the structure shown by FIG. 1.

The rifle barrel is shown at 1.

The warhead 2 of the projectile, of any suitable type, is provided with a rearward tubular extension 3 adapted to be mounted With a sliding fit on the muzzle end of barrel 1.

This tubular extension 3 carries, coaxially mounted in a slidable manner around it, an annular rocket motor 4. This rocket motor 4 includes an annular chamber 5, closed at the front and communicating at the rear with the atmosphere through an annular nozzle 6 (or a plurality of separate nozzles distributed about tube 1).

The axial sliding displacement of rocket motor 4 with respect to tubular extension 3 are limited in the rearward direction by a rear abutment element 7 carried by extension 3 arranged to cooperate with a suitable abutment element 8 of rocket motor 4.

The frontward axial displacements of rocket motor 4 with respect to extension 3 are limited by a front abutment element, consisting in the example shown, of the rear face of the warhead and adapted to cooperate with a corresponding abutment element 19 consisting for instance of the front edge of rocket motor 4.

The maximum sliding displacement permitted by these abutment elements between the projectile and the rocket is indicated at X on FIG. 1.

If, when the projectile is set for being launched, abutments 7 and 8 are at a distance (and preferably at the maximum distance) from each other, the thrust of the powdergases in barrel 1 acts only on the projectile proper (warhead 2 and its extension 3), rocket motor 4 remaining temporarily at rest so that its weight does not influence the recoil of the firearm.

Means are provided to ignite the propelling charge of rocket motor 4 and preferably the whole is arranged in such manner that the thrust of the rocket is sufficient to prevent abutment element 7 from coming into contact with abutment element 8, abutment element It) coming to bear upon abutment element 9 to transmit the thrust of said rocket to the projectile.

Of course, the various factors to be taken into account (such as the charge of the cartridge fired in the firearm, the nature and the weight of the propelling charge of the rocket motor, the dimensional characteristics of said rocket motor and in particular of the nozzle thereof, the value of distance X) can be determined in every case, either by calculation or by experimentation, so as to obtain the operation above described.

Of course, the means for igniting the charge of the rocket motor may be of any kind, for instance they may be electric means.

In the particular example shown by the drawing, the front end of tubular extension 3 is provided with a passage 11 capable, after the projectile has moved a short distance relatively to rocket motor 4, of communicating through a conduit 12 with the front end of the chamber 5 of said rocket motor. Thus, the propelling charge of the rocket motor will be ignited as soon as the projectile has just started moving, the communication between passage 11 and conduit 12 being subsequently closed by further relative forward movement of the projectile.

It should be noted that passage 11 may quite well communicate with the outside as long as it is cleared by the rearward relative movement of the rocket motor with respect to the projectile. During this period, some technical advantages will be obtained due to the existence of passage 11, such as relatively smooth disengagement of tubular extension 3 from barrel 1, a propelling action exerted on the projectile by the reaction due to the gases issuing through passage 11 and possibly a rotation imparted to the projectile about its axis if the direction of the outlet of passage 11 is suitably chosen. In order to make the device symmetrical, a second passage 11, but Without a corresponding conduit 12, may be provided, such as shown in dot-and-dash lines at 11 on FIG. 2, this passage l1 opening into the wall of tubular extension 3 at a point diametrally opposed to that Where passage 11 opens.

Preferably, in order to avoid a sudden increase of the recoil in the case of the rocket motor failing to be ignited, means are provided so that, before the projectile has moved a distance X relatively to the rocket motor, the gases which up to then were entrapped in the firearm barrel are allowed to escape to the outside.

For this purpose, in the construction shown by the drawing, when the projectile has moved a distance Y (smaller than X), the relative gastightness which existed up to then between tubular extension 3 and barrel 1 ceases to exist due to the fact that the diameter of the inner wall of tubular extension 3 suddenly increases at 13, whereby the gases in the barrel can escape to the outside through annular space between barrel 1 and tubular extension 5.

Preferably also, safety means are provided between abutment elements and it so that, as long as these elements have not come into contact with each other as a consequence of the projectile being launched, said projectile cannot burs For this purpose, in the example shown, a push-piece I14, as long as it has not been pushed back by contact element 10, prevents the operation of the electric fuze of the projectile.

Of course the projectile is provided with conventional stabilizing fins carried by the rear end of rocket Furthermore, barrel It is advantageously provided with a deflecting shield 16 intended to act as a protection against the combustion gases issuing from nozzle 6.

In a general manner, while I have, in the above description, disclosed what I deem to be practical and efficient embodiments of my invention, it should be well understood that I do not wish to be limited thereto as there might be changes made in the arrangement, disposition and form of the parts without departing from the principle of the present invention as comprehended within the scope of the accompanying claims.

What I claim is:

l. A projectile intended to be launched from a firearm barrel which comprises, in combination, a body forming the projectile proper, means rigid with said body for slidably engaging the launching firearm barrel to transmit to said body the thrust of powder gases in said barrel, an auxiliary jet motor for propulsion of said projectile mounted slidable in the fore and aft direction with respect to said body, said jet motor being di posed laterally of the above-mentioned means so as to undergo no propelling action from the powder gases in said barrel, two abutments, a front one and a rear one, carried by said body in fixed position with respect thereto, said abutments being mounted to cooperate with portions of said auxiliary motor to limit the sliding displacements thereof with respect to said body, the portion of said auxiliary motor cooperating with the rear abutment being at a distance from said rear abutment when said projectile is set for launching, and means responsive to the initial forward accelerution of said projectile upon launching for starting said auxiliary motor into operation as soon as said projectile has moved forward, whereby said auxiliary motor transmits a propulsive effort to said projectile body through said front abutment.

2. A projectile intended to be launched from a firearm barrel which comprises, in combination, a body forming the projectile proper, means rigid with said body for slidably engaging the launching firearm barrel to transmit to said body the thrust of powder gases in said barrel, an auxiliary jet motor for propulsion of said projectile mounted slidable in the fore and aft direction with respect to said body, said jet motor being disposed laterally of the above-mentioned means so as to undergo no propelling action from the powder gases in said barrel, two abutments, a front one and a rear one, carried by said body in fixed position with respect thereto, said abutments being mounted to cooperate with portions of said auxiliary motor to limit the sliding displacement thereof with respect to said body, the portion of said auxiliary motor cooperating with the rear abutment being at a distance from said rear abutment when said projectile is set for launching, and means responsive to the initial forward acceleration of said projectile upon launching for starting said auxiliary motor into operation as soon as said projectile has moved forward, whereby said auxiliary motor transmits a propulsive effort to said projectile body through said front abutment, said last mentioned means and said auxiliary motor being such that the propulsive thrust developed by said motor prevents it from being contacted by said rear abutment when said projectile is launched.

3. A projectile intended to be launched from a firearm barrel which comprises, in combination, a body forming the projectile proper, a tubular rearward extension of said body rigid therewith along the axis thereof, said tubular extension being adapted to fit slidably on the end of the launching firearm barrel to transmit to said body the thrust of powder gases in said barrel, auxiliary motor means for propulsion of said projectile consisting of an annular rocket motor surrounding said tubular extension coaxially therewith and undergoing no propelling action from the powder gases in said barrel, the annular nozzle of said rocket motor being at the rear thereof, said rocket motor being slidable longitudinally with respect to said extension, a rear abutment carried by said extension in fixed position and adapted to cooperate with a portion of said rocket motor to limit relative displacements of said rocket motor toward the rear with respect to said extension, a front abutment carried by said projectile in fixed position thereon and adapted to cooperate with said rocket motor to limit relative displacements of said rocket motor toward the front with respect to said projectile, said rocket motor being at a distance from said rear abutment when said projectile is set for launching, and means for igniting said rocket motor in response to the launching of said projectile from said barrel, whereby said rocket motor transmits a propulsive effort to said projectile body through said front abutment, said igniting means and said rocket motor being such that the propulsive thrust developed by said rocket motor prevents it from being contacted by said rear abutment when said projectile is launched.

4. A projectile according to claim 3 in which said means for igniting said rocket motor includes a passage extending through the front end of said tubular extension, said rocket motor being provided with a corresponding conduit capable of connecting said passage with the inside of the rocket motor after the projectile has moved a sma l distance forwardly with respect to said rocket motor, whereby the rocket motor is ignited by the powder gases from the barrel of the firearm.

5. A projectile according to claim 1 further including means for connecting the inside of said tubular extension with the external atmosphere after the projectile has moved forwardly with respect to the auxiliary motor a distance smaller than the total relative displacement permitted by said abutments.

6. A projectile according to claim 1 further including means for preventing burs-ting of said projectile as long as said auxiliary motor has not come into contact with said front abutment.

References Cited in the file of this patent UNITED STATES PATENTS 2,700,337 Cumming Jan. 25, 1955 2,753,801 Cumming July 10, 1956 2,770,904 Weiss Nov. 20, 1956 2,801,586 Mongello Aug. 6, 1957 FOREIGN PATENTS 1,171,438 France Oct. 3, 1958 

1. A PROJECTILE INTENDED TO BE LAUNCHED FROM A FIREARM BARREL WHICH COMPRISES, IN COMBINATION, A BODY FORMING THE PROJECTILE PROPER, MEANS RIGID WITH SAID BODY FOR SLIDABLY ENGAGING THE LAUNCHING FIREARM BARREL TO TRANSMIT TO SAID BODY THE THRUST OF POWDER GASES IN SAID BARREL, AN AUXILIARY JET MOTOR FOR PROPULSION OF SAID PROJECTILE MOUNTED SLIDABLE IN THE FORE AND AFT DIRECTION WITH RESPECT TO SAID BODY, SAID JET MOTOR BEING DISPOSED LATERALLY OF THE ABOVE-MENTIONED MEANS SO AS TO UNDERGO NO PROPELLING ACTION FROM THE POWDER GASES IN SAID BARREL, TWO ABUTMENTS, A FRONT ONE AND A REAR ONE, CARRIED BY SAID BODY IN FIXED POSITION WITH RESPECT THERETO, SAID ABUTMENTS BEING MOUNTED TO COOPERATE WITH PORTIONS OF SAID AUXILIARY MOTOR TO LIMIT THE SLIDING DISPLACEMENTS THEREOF WITH RESPECT TO SAID BODY, THE PORTION OF SAID AUXILIARY MOTOR 